Making concrete foundation piers and the like



C. RJGOW ET Al.

MAKING CONCRETE FOUNDATION PIERs AND THE LIKE Filed May' 11.

Nov. *'23 1926.

Patented Nov. 23, 1.926.

Unita sra'rss PATENT i orrics.

CHARLES B. GOW, OE VEST ROXB'UY, AND LINTON HART, OF BROOKLINE,MASSACHU- SETTS, ASSGNORS T CHARLES R. GO'W' COMPANY. OF BOSTON,MASSACHUSETTS, A

CRPORATIN 0F MASSACHUSETTS.

MAKING CONCRETE FOUNBATION PIER-S AND TEE LIKE.

f Application filed May 11,

This invention relates to the construction or formation of concretepiers or,` columns inV situ for foundations and other purposes,`

and its chief object is to provide an effective and simple method kbywhich such colums of adequate strength and bearing capacity can beconstructed atv low cost through water bearing soil. In carrying shellsof successively smaller diameter, one inside of the other; the largestbeing driven down first, then the second inside ofthe first, the thirdinside of the second, and so Y on, through the lnon-waterbearing or drypart of the soil. After eachv'shell is driven,

and beforeA the next is sunk, the material en closed by the driven shellis removed, so that a hole isproduced having a temporary lining of steelwhich eifectually prevents cavh ing or slipping and therefore permitsworking close to existing foundations without injury thereto. `When thewaterbearing layer or stratum is reached or approached as may be knownby seepage or by previous sinkings or borings) the sinking of the casingshells ceases and in the lowermost a concrete lining cylinder isestablished, fitting the shell snugly, and, if desirable or neces` sary,sealed thereto by suitable packing or filling in any convenient mannerto exclude water. rThis concrete cylinder, which is left permanently inthe ground may be cast in place or it may be cast outside and insertedinto the shell at the proper time. In the concrete cylinder an air lockis placed, through which air pressure is applied below the lock toprevent excessive seepage. Excavation is now continued below the lock,and as the shaft ldeepens its sides are covered or lined with wood,metal, or other sheathing suiliciently firm and tight to prevent cavingin of thewalls or inow of soft mate` rial. This operation is carrieddown to the rock or hard bearing material on which the pier is to rest.VWhile the air pressure is maintained the sheathed portion ofthe holeisfilled with concrete' and the filling carried up intoVA the concreteliningv cylinder far enough to serve as a seal against excessiveseepageinto the cylinder from below. As soon as the .concrete issufficiently hard to make thefseal effective the'airpressureds 1923.Serial No. 638,172.

relieved and the air lock removed. filling is nowcontinued in the openkair, and as the filling proceeds the steel shells are withdrawn from thehole for re-use, the concrete lining cylinder, lion-ever, being leftpermanently inthe ground.

- The method outlined above is illustrated in various stages in thelaccompanying drawings, in which- Y Y Figi is a vertical section showingthe shaft-completed down to rock or bearing materiakready for theconcrete seal.

Fig, 2 is asimilar section showing the concrete seal in been removed.

Fig. 3 is a vertical section showing the completed pier or column.

F d is a detail verticalsection showing the lower or bearing end ofthecolumn, provided. with an enlarged footing to distribute,

the load over a larger area of the rocker bearing material. y,

As indicated in 'the drawings, the steel shellslO, 11, l2, of anysuitable size and preferably cylindrical in form, are of successivelysmaller diameter so that one can descend through the other. They areused to provide a temporary lining for the upper part of the hole, beingeventually removed as explained hereinafter. rlhe largest shell is firstdriven or otherwise sunk in the ground, followed by the others in order,the soil in the last driven being removed before the next is sunk. Threesuch shells are shown, but of course the precise number is immaterial,and depends upon the length of the individual sections or shells 'andthe depth at which seepage or inflow becomes or would become excessive.Vhen such point is reached the sinking of the lining shells ceases, anda hollow concrete lining cylinder or caisson 13 is established in thelowermost shell. This caisson or cylinder may be cast outside andinserted into the hole, or it may be cast in place. Preferably it islonger than the shell and is sunk somevdistance below the same, as by'excavating under it, but in most cases it should project into theshell, so as to prevent excessive seepage orfinflow of water or soft'material at a later stage ofthe work. lIf lthe caisson, which is toconstitute a part of the permanent lining of the-hole, and may containreinforcing members (not shown )l in its walls, is cast in placeremovable forms (not shown)- niay be used if'necessary or desirable tomake a caisson of the desired length, or, in some cases, it conditionspermit, the ground below the lowest shell can be excavated and the bareearth sides of the hole can serve as the outer form or mold below theshell. 1i' necessary or desirable, the caisson may be calked or packedin place in any convenient and suitable manner, not shown. Y

Vv'hen the walls ot the lining caisson are suliiciently hard an airlock, lshown diagrammatically at 14e, is positioned therein, tar enoughabove the bottom to permit excavation to be carried on under it by anymethod suited to the existing conditionsf Air is pumped into the airlock andthrough the samefinto the caisson below, and suliicient pressureis maintained to prevent the work being interfered with by excessiveseepage;

'As the hole below the caisson is deepened its sides are lined orsheathed 'with' lining members 15, made of wood, metal, or othermaterial. rlfhese members may be segmental in form so as to be arrangedend to end circumferentially, and of course are of a' size to permittheir introduction through the air lock. Continuingl the excavation andsheathing of the hole, under the necessary air pressure, until rock orhard bearing material 16 'is reached, we then have the stage illustratedin F ig. 1, the hole being lined all the way down to prevent caving orslippage and under suiiicient internal air pressure to prevent undueseepage.

` le now introduce concrete 17, through the air'lock and lill thesheathed portion of the hole, preferably carrying the filling up intothe open lower end of the caisson, as indicated in Fig. iar enough toinsure against excessive iniow of water 'from below after the airpressure is relieved. 'Vhen the concrete, which serves afterward as thelower portion of the column, has set hard enough to enable it to serveas a seal which will exclude undue seepage, the air lock is removed andthe concrete filling is continued to the desired height. As the lillingis carried up, the steel shells 13, 12, etc., are uulled outin advance,one after the other. y e vlowest shell can usually 'be` pulled ybeforeor after the caisson 18 is filled, and in some cases "before the' holevbelow is excavated. In most cases the shell'next above withdrawn assoonas the caisson'is lill'ed, then the hole lett by the -shellwithdrawn is filled and-theV work continued in this manner until thefilling is Lcompleted'andfithe last shell pulled out. Insemesituationsfas Afor example' --whereexeessve lateral` pressures areencountered, it vmay be-necessaryto let the successivelv r fillings set`ly-enough te resist such pressures 'be'orepull-ing the: shell nextabe-fe. In 'this l`way" it yie'solnetimes possible to remove all theshells under conditions which'would otherwise make such course dangerousif not impossible.

Below the caisson the sides of the excavation, and. hence the. sides ofthat portion of: the completed pier, may be substantially parallel, asindicated in Figs. 1, 2 and 3, or they tavernes@ 01';- laSS. Spread O10WD- ward iiare, beginning at any desired point. Thus in Fig. Alis shownthe lower portion oi' a pier or column with the flare beginning a shortdistance above the rock 16, terror-1n a belled orenlarged footing bywhich the total load is distributed over a'larger area and the load perunit area thereby decreased.

It is to be understood that the operations described in the foregoingconstitute the preferred practice,'but that the invention can be carriedout in other ways without departure from its spirit as defined bytheJfollowing claims. Y 1 l lalle claim--Y 1. 1n ainethod of formingconcrete piers and the like in situ,-sinking into theV ground througheach other a series of shells of successivelyl 4less diameter andremoving the soil from each shell before the next is sunk, therebylforming a hole having a temporary lining capable of resisting cavingand slippage due to lateral pressure; establishing in the lowest shell apermanent lining section in the form of a hollow concrete caisson and byair pressure therein preventing undue seepage from below; excavatingbelow the permanent lining section to the desired depth and lining thesides of the excavation, while maintaining an air pressure adequate toprevent excessive seepage; depositi-ng concrete in the hole andmaintaining the air pressure until the concrete has set firmly enough.to seal the concrete lining section against undue seepage or the like;and thereafter relieving the pressure and filling the concrete liningand the hole above, and withdrawing vthe shells from the ground insuccession as the illing proceeds.

Q. n a method of forming concrete piers and the like in situ, sinking insuccession, through each other into the ground, a series or removableconcentric shells of successively smaller diameter and removing the soilfrom thev shells as the sinking thereo prbceeds; establishing in thelower shell a hollow liningsection to seal the hold-excavati-ngbelow thecaisson to the desired depth andsheathingthe 'sides off-the excavation,and thereafter filling the helewith concrete to-forma pier-ot thedesired height, and

withdrawing thelining shells.

Ina Vmeti-ind of--orin-ingconcrete piers and the like in situ, sinkingiii-succession, thfreugh each .other-'into the-ground, a series ofremovable shells-otsuccessively smaller diameter 'and -iemovin-g thesoil Y-'therefrom le-ivres@"temrefarlyrlined hele, establishing in thelower shell a hollow caisson to seal the hole and forming a permanentlinine' for a part of the hole, extending the hole below the caisson byexcavating under air pressure adequate to prevent undue inflow of water,and sheathing the sides of the excavation to maintain the walls thereof;depositing concrete in the hole below the caisson and allowing theconcrete to harden under pressure until firm enough to permit thepressure to be relieved; and thereafter continuing the filling in theopen air.

l. ln a method of forming concrete piers and the like in situ, sinkinginto the ground in succession a series of removable shells andreinovii'ig the soil therefrom to form a lined hole, establishing alining caisson therein, extending the hole below the caisson byexcavating below the same under air pressure through an air lock in thecaisson while maintaining the walls of the excavation against caving orthe like, filling the hole below the caisson with concrete, and when thesame has hardened suiiiciently relieving` the air pressure, andthereafter continuing the filling and removing the Yshells in successionas the filling is extended into the shell-lined portion of the hole.

5. ln a method of forming concrete piers and the like in situ, sinkinginto the ground in succession a. series of removable shells and removingthe soil therefrom to form a temporarily lined hole, establishing ahollow concrete caisson therein to serve as a permanent lining for aportion of the hole and applying air pressure through the caisson toexclude excessive inflow of water from below, deepening the hole belowthe permanently lined portion 'by excavating below the same under saidair pressure, and

'scaling the lower end of the caisson with concrete to prevent undueinflow into the saine after the air pressure is relieved.

t3. In a method of forming concrete piers and the like in situ, sinkinginto the ground a series of shells and removing the soil therefrom,establishing a caisson therein and applying air pressure through thelining caisson to prevent excessive inflow of water from below,deepening thehole below the lining caisson by excavating below the sameunder said air pressure and lining the deepcned portion to maintain thewalls thereof against collapse, filling the said deepened portion of thehole with concrete and sealing therewith the lower end of the liningcaisson to prevent undue inflow after the air pressure is relieved, andthereafter filling the hole with concrete in the open air.

7. ln a method of forming concrete piers and the like in situ, formingin the ground a hole having a temporary lining down to a point wherefurther deepening of the hole would cause excessive inflow of water,establishing a lining caisson therein and applying air pressure throughthe caisson to prevent said excessive inflow, excavating under airpressure below the caisson to deepen the hole and maintaining the wallsof the deepened portion against collapse, depositing concrete in saiddeepened portion and under said air pressure sealing with the concretethe lower end of the caisson to prevent excessive inflow of water aftertheV air pressure is relieved, and thereafter in the open air filling'the hole with concrete above the seal.

8c ln a method of forming concrete piers and the like in situ, forming ahole in the ground and providing the same with a temporary liningcomposed of removable lining members, establishing in the lower portionof the temporary lining a permanent lining section of concrete,excavating below the permanent lining section to deepen the hole,sealing the said deepened portion of the hole and the bottom of thepermanentlining section with concrete to exclude water, and filling thepermanently and temporarily lined portions with concrete and removingthe removable lining members from the upper portion of the hole.

In testimony whereof we hereto affix our signatures.

CHARLES R. GOV. LINTON HART.

